do you have some pointers, papers to the work of this guys? I am interested in learning what is that about Nick
http://www.linkedin.com/in/tnick Sent from Ünalan, İstanbul, Turkey On Fri, Jan 15, 2010 at 11:01 PM, Wojciech Lewandowski < [email protected]> wrote: > Nick, > > I may look into the code but don't expect much this time. You need to > attach the code first, though ;-). Few academy guys wrote > couple dissertations on rasterization and aliasing errors in shadow > mapping. Unless you try to do some exotic stuff like variance or logarithmic > map you will have to use polygon offset. I guess you will end up to > cranking up PolygonOfset even more if current values fail at some distance. > I don't really have other tricks in my sleeve. > > Wojtek > > > *From:* Trajce Nikolov <[email protected]> > *Sent:* Friday, January 15, 2010 9:08 PM > *To:* OpenSceneGraph Users <[email protected]> > *Subject:* Re: [osg-users] light lobes and shadow maps > > That is exactly what I did. Please have a look at the updated code. The > uniform is updated thru a callback and it multiplies the matrices, still > there is a visual artifact.I dont have compute_near_far. The projection > matrix is fixed with very small far plane (100 units, with the znear of > 0.01). > > Nick > > http://www.linkedin.com/in/tnick > > > On Fri, Jan 15, 2010 at 9:47 PM, Wojciech Lewandowski < > [email protected]> wrote: > >> Hi, >> >> Light close to obstacles ? If you have COMPUTE_NEAR_FAR it may clamp near >> plane to very small value which may impact depth resolution. Other issue >> maybe related to GLSL float precision. The trick with multiplying view >> space coord by inverse view matrix to get world coord is performed on float >> values inside GLSL. Precision wise it would be better to multiply light >> camera MVP matrix by main camera INVERSE VIEW on the CPU. Osg Matrices use >> doubles. Put the result of the multiplication on GLSL matrix Uniform and >> use it to multiply gl_Vertex in the shader. Such approach multiplies >> matrices with high precision and resulting matrix will be better suited to >> be cast on single prec. GLSL matrix. The drawback of this solution is: you >> need to update the uniform every frame, because main camera view changes >> with each move. >> >> Wojtek >> >> >> *From:* Trajce Nikolov <[email protected]> >> *Sent:* Friday, January 15, 2010 7:37 PM >> *To:* OpenSceneGraph Users <[email protected]> >> *Subject:* Re: [osg-users] light lobes and shadow maps >> >> Hi Wojtek, >> >> now I spent more time exploring this, the polyoffset seam to work, but >> there is still a bit of shimmering. Its interesting, I put the light source >> in move, when it moves backwards, the obstacles are lighten ok, but forward, >> when the light comes close to the obstacles, the lighting is incorrect with >> shimmering . Any clue how to resolve this artifact ? >> >> Nick >> >> http://www.linkedin.com/in/tnick >> >> >> On Fri, Jan 15, 2010 at 4:48 PM, Trajce Nikolov <[email protected] >> > wrote: >> >>> ok .. make sense. Here is updated code, if some one wants to benefit >>> from. LightLobes with handling of obstacles :). Thanks to Wojiech, Robert >>> and the online community >>> >>> Nick >>> >>> http://www.linkedin.com/in/tnick >>> Sent from Devlet, Ankara, Turkey >>> >>> On Fri, Jan 15, 2010 at 3:53 PM, Wojciech Lewandowski < >>> [email protected]> wrote: >>> >>>> 0.0 <= shadow2DProj( shadow_texture, projShadow ).r <= 1.0 >>>> >>>> Shimering is a result of self shadowing. Boosting depths in shadow map >>>> with glPolygonOffset usuallly fixes this. There are many schools for >>>> PolygonOffset settings. I usually set glPolygonOffset( 1.1, 4.0 ) and draw >>>> objects with front face culling (see StandardShadowMap::ViewData::init(0 >>>> for >>>> details ). But for this setup models need to work correctly with backface >>>> culling on. If you do not enforce backface culling PolygonOffset may need >>>> different initialization. >>>> >>>> Wojtek >>>> >>>> ----- Original Message ----- >>>> >>>> *From:* Trajce Nikolov <[email protected]> >>>> *To:* OpenSceneGraph Users <[email protected]> >>>> *Sent:* Friday, January 15, 2010 2:46 PM >>>> *Subject:* Re: [osg-users] light lobes and shadow maps >>>> >>>> one more question. What are the possible values for shadow2DProj( >>>> shadow_texture, projShadow ).r ? I am trying to put the light attenuation >>>> back ..... and to avoid the shimmering >>>> Nick >>>> >>>> http://www.linkedin.com/in/tnick >>>> Sent from Devlet, Ankara, Turkey >>>> >>>> On Fri, Jan 15, 2010 at 3:35 PM, Trajce Nikolov < >>>> [email protected]> wrote: >>>> >>>>> Hey Wojtek !!!! Thanks a lot. !! I will tune it to fix the shimmering >>>>> >>>>> >>>>> Nick >>>>> >>>>> http://www.linkedin.com/in/tnick >>>>> >>>>> >>>>> On Fri, Jan 15, 2010 at 3:08 PM, Wojciech Lewandowski < >>>>> [email protected]> wrote: >>>>> >>>>>> Trajce, >>>>>> >>>>>> Attached is a fixed source code. There is a lots of shadow shimmering >>>>>> on my GF8800. You will have to add some depth bias while rendering shadow >>>>>> map. Selection proper PolygonOffset values is usually a matter of trial >>>>>> and >>>>>> error so leave this for you. >>>>>> >>>>>> Wojtek >>>>>> >>>>>> ----- Original Message ----- >>>>>> >>>>>> *From:* Trajce Nikolov <[email protected]> >>>>>> *To:* OpenSceneGraph Users <[email protected]> >>>>>> *Sent:* Friday, January 15, 2010 9:58 AM >>>>>> *Subject:* Re: [osg-users] light lobes and shadow maps >>>>>> >>>>>> ABout the code. I use shader to simulate lght lobes thru phong >>>>>> lighting in the shader. Then I use shadow maps to detect the area behind >>>>>> the >>>>>> obstacles that need not to be lighten. Most is mixture of shadow maps >>>>>> technique with lighting scheme. Code snippets borrowed from all around >>>>>> >>>>>> Nick >>>>>> >>>>>> http://www.linkedin.com/in/tnick >>>>>> Sent from Devlet, Ankara, Turkey >>>>>> >>>>>> On Fri, Jan 15, 2010 at 10:54 AM, Trajce Nikolov < >>>>>> [email protected]> wrote: >>>>>> >>>>>>> Hi Guys, >>>>>>> >>>>>>> here is the code. >>>>>>> >>>>>>> Nick >>>>>>> >>>>>>> http://www.linkedin.com/in/tnick >>>>>>> Sent from Devlet, Ankara, Turkey >>>>>>> >>>>>>> On Thu, Jan 14, 2010 at 11:42 PM, Wojciech Lewandowski < >>>>>>> [email protected]> wrote: >>>>>>> >>>>>>>> Hi Nick, >>>>>>>> >>>>>>>> Post the troublesome code and elaborate a bit more about the >>>>>>>> problem. If its really a minute or two I am sure someone will be able >>>>>>>> to >>>>>>>> help. >>>>>>>> >>>>>>>> Wojtek Lewandowski >>>>>>>> >>>>>>>> *From:* Trajce Nikolov <[email protected]> >>>>>>>> *Sent:* Thursday, January 14, 2010 8:58 PM >>>>>>>> *To:* OpenSceneGraph Users <[email protected]> >>>>>>>> *Subject:* [osg-users] light lobes and shadow maps >>>>>>>> >>>>>>>> Hi community, >>>>>>>> >>>>>>>> I have some shader that does some lighting in the scene. Now >>>>>>>> studying osgShadow and the techniques. I want to a shadow map >>>>>>>> technique to >>>>>>>> disable the lightening of the scene behind obstacles. I have some code >>>>>>>> done, >>>>>>>> but not working. I need some help, someone experienced with GLSL to >>>>>>>> spend a >>>>>>>> minute or to to have a look and if possible to spot the problem. >>>>>>>> Anyone? >>>>>>>> >>>>>>>> Thanks a lot >>>>>>>> >>>>>>>> Nick >>>>>>>> >>>>>>>> http://www.linkedin.com/in/tnick >>>>>>>> Sent from Izmit, 41, Turkey >>>>>>>> >>>>>>>> ------------------------------ >>>>>>>> >>>>>>>> _______________________________________________ >>>>>>>> osg-users mailing list >>>>>>>> [email protected] >>>>>>>> >>>>>>>> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org >>>>>>>> >>>>>>>> >>>>>>>> _______________________________________________ >>>>>>>> osg-users mailing list >>>>>>>> [email protected] >>>>>>>> >>>>>>>> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org >>>>>>>> >>>>>>>> >>>>>>> >>>>>> ------------------------------ >>>>>> >>>>>> _______________________________________________ >>>>>> osg-users mailing list >>>>>> [email protected] >>>>>> >>>>>> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org >>>>>> >>>>>> >>>>>> _______________________________________________ >>>>>> osg-users mailing list >>>>>> [email protected] >>>>>> >>>>>> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org >>>>>> >>>>>> >>>>> >>>> ------------------------------ >>>> >>>> _______________________________________________ >>>> osg-users mailing list >>>> [email protected] >>>> >>>> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org >>>> >>>> >>>> _______________________________________________ >>>> osg-users mailing list >>>> [email protected] >>>> >>>> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org >>>> >>>> >>> >> ------------------------------ >> >> _______________________________________________ >> osg-users mailing list >> [email protected] >> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org >> >> >> _______________________________________________ >> osg-users mailing list >> [email protected] >> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org >> >> > ------------------------------ > > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > > > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > >
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